Question

The spectrophotometer measures what property of a solution? Group of answer choices
A. The ability of the solute and solvent molecules (AKA a soloution) to absorb the energy of light (photons) at a specific wavelength of light (spectrum).
B. The ability of the solute molecules only to absorb the energy of light (photons) at a specific wavelength.
C. The ability of the solvent molecules only to absorb the energy of light (photons) at a specific wavelength because there are many more solvent than solute molecules.
D. The ability of the solute and solvent molecules to absorb the energy of light (photons) at a all wavelengths of the light spectrum at once.
E. Then the spectrophotometer sorts it out.

Answer 1

Answer:

B. The ability of the solute molecules only to absorb the energy of light (photons) at a specific wavelength.

Explanation:

Spectrophotometry is the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength. In case of a solution, both, solute and solvent would absorb the energy on an specific lenghtwave of light if they have a absortion coefficient diffrent of 0. The solvent could absorb energy of light, but it´s not typical, for example water does not absorb light in any lenghtwave. Therefore, for practical uses, we consider that only the solute absorbes, and it case the solvent does, that should be taken into account for the solute concentration calculation.